The objective of this project is the research and development of suitable analytical methods to: (1) establish the structure and purity of potential anti-AIDS agents and new antiviral drugs, (2) determine physical and chemical properties of these compounds and their metabolites, and (3) measure these drugs and their metabolites in biological samples to elucidate pharmacology and to determine pharmacokinetics. Gas chromatography, high-performance liquid chromatography and mass spectrometry are emphasized techniques. Compounds of current interest are dideoxycytidine, dideoxyadenosine, 2',3'-dideoxy-5-fluorocytidine, 2',3'-dideoxy- 2'-beta-fluoroadenosine and 2',3'-dideoxy-2'-beta-fluoroinosine.